Coil component and circuit board having the same

ABSTRACT

Disclosed herein is a coil component that includes a drum-shaped core having a first flange part provided at one end of a winding core part, first to fourth terminal electrodes formed on the first flange part so as to be arranged in this order in a second direction, and first to fourth wires wound around the winding core part. One ends of the first to fourth wires are connected to different ones of the first to fourth terminal electrodes. The first and second terminal electrodes are not symmetrical with the third and fourth terminal electrodes so that the third and fourth terminal electrodes are offset outward compared with the first and second terminal electrodes.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a coil component and a circuit boardhaving the same and, more particularly, to a coil component using adrum-shaped core and a circuit board having the same.

Description of Related Art

In recent years, electronic components used for an information terminalsuch as a smartphone are strongly required to reduce the size andparticularly height thereof. Thus, a large number of surface-mount typecoil components not using a toroidal-shaped core but using a drum-shapedcore exist as a coil component such as a pulse transformer. For example,Japanese Patent Application Laid-Open No. 2014-199906 discloses asurface-mount type pulse transformer using a drum-shaped core.

The drum-shaped core of the pulse transformer descried in JapanesePatent Application Laid-Open No. 2014-199906 has a configuration inwhich the mounting surface at the flange thereof has a concave-convexshape and the end portion of a wire is connected onto the convex part,as illustrated in FIG. 2 of Japanese Patent Application Laid-Open No.2014-199906. On the other hand, a terminal electrode is not formed onthe outer surface of the flange. With such a configuration, when thepulse transformer described in Japanese Patent Application Laid-Open No.2014-199906 is mounted on a printed circuit board, a solder is formedbetween a land pattern on the printed circuit board and the convex partof the flange. Since the terminal electrode is not formed on the outersurface of the flange, a solder fillet is not formed on the outersurface.

In recent years, particularly, an on-vehicle coil component is requiredto have higher reliability than ever before. To meet this requirement,it is important to form a solder fillet when the coil component ismounted. It is necessary to form a terminal electrode on the outersurface of a flange in order to form a solder fillet; however, eddycurrent loss increase when a terminal electrode is formed on the outersurface of a flange.

SUMMARY

An object of the present invention is therefore to provide a coilcomponent in which a terminal electrode is provided on the outer surfaceof the flange thereof and eddy current loss is reduced and a circuitboard with the coil component.

A coil component according to the present invention includes:

a drum-shaped core including:

-   -   a winding core part, an axial direction of the winding core part        being a first direction;    -   a first flange part provided at one end of the winding core part        in the first direction; and    -   a second flange part provided at other end of the winding core        part in the first direction;

first to fourth terminal electrodes formed on the first flange part soas to be arranged in this order in a second direction substantiallyperpendicular to the first direction;

fifth to eighth terminal electrodes formed on the second flange part soas to be arranged in this order in the second direction; and

first to fourth wires wound around the winding core part, one ends ofthe first to fourth wires being connected to different ones of the firstto fourth terminal electrodes and other ends of the first to fourthwires being connected to different ones of the fifth to eighth terminalelectrodes, wherein

the first flange part has a first inner side surface connected to thewinding core part and a first outer side surface opposite to the firstinner side surface,

the second flange part has a second inner side surface connected to thewinding core part and a second outer side surface opposite to the secondinner side surface,

the first to fourth terminal electrodes are formed at least on the firstouter side surface,

the fifth to eighth terminal electrodes are formed at least on thesecond outer side surface,

a distance between the first and second terminal electrodes in thesecond direction is larger than the distance between the third andfourth terminal electrodes in the second direction,

a distance between the fifth and sixth terminal electrodes in the seconddirection is larger than the distance between the seventh and eighthterminal electrodes in the second direction,

a distance between a first virtual line and the third terminal electrodein the second direction is larger than a distance between the firstvirtual line and the second terminal electrode in the second direction,where the first virtual line is defined on the first outer side surface,extends in a third direction substantially perpendicular to the firstand second directions, and whose position in the second directioncoincides with the center axis of the winding core part, and

a distance between a second virtual line and the seventh terminalelectrode in the second direction is larger than a distance between thesecond virtual line and the sixth terminal electrode in the seconddirection, where the second virtual line is defined on the second outerside surface, extends in the third direction, and whose position in thesecond direction coincides with the center axis of the winding corepart.

A circuit board according to the present invention includes: a substratehaving a plurality of land patterns; the coil component mounted on thesubstrate; and solders that connect the plurality of land patterns andthe first to eighth terminal electrodes. The plurality of land patternsinclude first, second, third, and fourth land patterns connectedrespectively to the first, second, fifth, and sixth terminal electrodes,a fifth land pattern connected in common to the third and fourthterminal electrodes, and a sixth land pattern connected in common to theseventh and eighth terminal electrodes.

According to the present invention, the first and second terminalelectrodes (or fifth and sixth terminal electrodes) are not symmetricalwith the third and fourth terminal electrodes (or seventh and eighthterminal electrodes). That is, the third and fourth terminal electrodes(or seventh and eighth terminal electrodes) are offset outward, so thateddy current loss can be reduced. In addition, a sufficient distance isensured between the first and second terminal electrodes (or distancebetween the fifth and sixth terminal electrodes), so that even whenthese terminal electrodes are connected to mutually different landpatterns, occurrence of a short circuit fault can be prevented. Further,the distance between the third and fourth terminal electrodes (distancebetween the seventh and eighth terminal electrodes) is small, so thatwhen these terminal electrodes are used as a center tap of a pulsetransformer, they can be reliably short-circuited by a bridge of thesolder.

Preferably, in the present invention, the first to eighth terminalelectrodes do not overlap the winding core part as viewed in the firstdirection. With this configuration, eddy current loss can be furtherreduced.

Preferably, in the present invention, a distance between the fourthterminal electrode and one end portion of the first outer surface in thesecond direction is smaller than a distance between the first terminalelectrode and other end portion of the first outer surface in the seconddirection, and a distance between the eighth terminal electrode and oneend portion of the second outer surface in the second direction issmaller than the distance between the fifth terminal electrode and otherend portion of the second outer surface in the second direction. Withthis configuration, eddy current loss can be further reduced.

Preferably, in the present invention, the first flange part further hasa first bottom surface substantially parallel to the first and seconddirections, the second flange part further has a second bottom surfacesubstantially parallel to the first and second directions, the first tofourth terminal electrodes are further formed on the first bottomsurface, the fifth to eighth terminal electrodes are further formed onthe second bottom surface, the one end of each of the first to fourthwires contacts with each of the first to fourth terminal electrodes onthe first bottom surface, and the other end of each of the first tofourth wires contacts with each of the fifth to eighth terminalelectrodes on the second bottom surface. With this configuration, wireconnection can be easily achieved.

In this case, it is preferable that each of the first to fourth terminalelectrodes is a L-shaped metal fitting covering the first outer surfaceand the first bottom surface, and each of the fifth to eighth terminalelectrodes is a L-shaped metal fitting covering the second outer surfaceand the second bottom surface. With this configuration, a manufacturingcost of the coil component can be reduced.

Preferably, in the present invention, the coil component further has aplate core, wherein the first flange part further has a first topsurface opposite to the first bottom surface, the second flange partfurther has a second top surface opposite to the second bottom surface,and the plate core is bonded to the first and second top surfaces. Withthis configuration, high magnetic characteristics can be obtained.

According to the present invention, eddy current caused by the terminalelectrodes provided on the outer side surface of the flange part can beprevented, so that it is possible to provide a coil component with lesseddy current loss and a circuit board provided with the coil component.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of this inventionwill become more apparent by reference to the following detaileddescription of the invention taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a schematic perspective view illustrating an externalstructure of a coil component according to a preferred embodiment of thepresent invention;

FIGS. 2 and 3 are side views of the coil component shown in FIG. 1 asseen from the y-direction;

FIG. 4 is a plan view illustrating a conductor pattern on a substrate onwhich the coil component is mounted;

FIG. 5 is a circuit diagram of a LAN connector circuit (100Base);

FIG. 6 is a circuit diagram of a LAN connector circuit (1000Base); and

FIG. 7 is a side view of the coil component mounted on the substrate.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be explained indetail with reference to the drawings.

FIG. 1 is a schematic perspective view illustrating an externalstructure of a coil component 10 according to a preferred embodiment ofthe present invention.

The coil component 10 according to the present embodiment is asurface-mount type pulse transformer. As illustrated in FIG. 1, the coilcomponent 10 includes a drum-shaped core 20, a plate core 30 bonded tothe drum-shaped core 20, and wires W1 to W4 wound around a winding corepart 21 of the drum-shaped core 20. The coil component according to thepresent invention is not limited to a pulse transformer, but may beother transformer components such as a balun transformer and a boostertransformer or filter components such as a common mode choke coil.

The drum-shaped core 20 and the plate core 30 are formed of a magneticmaterial having comparatively high permeability, such as a sintered bodyof a Ni—Zn ferrite or Mn—Zn ferrite. In general, a magnetic materialhaving high permeability, such as Mn—Zn ferrite, is low in specificresistance and has conductivity.

The drum-shaped core 20 has a rod-like winding core part 21 whose axialdirection is the y-direction, and first and second flange parts 22 and23 provided at both ends of the winding core part 21 in the y-direction.The winding core part 21 and flange parts 22 and 23 are integrallyformed. The flange part 22 has an inner side surface 22 i connected tothe winding core part 21, an outer side surface 22 o positioned on theopposite side of the inner side surface 22 i, a bottom surface 22 bextending parallel to the axial direction of the winding core part 21,and a top surface 22 t positioned on the opposite side of the bottomsurface 22 b. Similarly, the flange part 23 has an inner side surface 23i connected to the winding core part 21, an outer side surface 23 opositioned on the opposite side of the inner side surface 23 i, a bottomsurface 23 b extending parallel to the axial direction of the windingcore part 21, and a top surface 23 t positioned on the opposite side ofthe bottom surface 23 b. The inner side surfaces 22 i and 23 i and theouter side surfaces 22 o and 23 o constitute the xz plane, and bottomsurfaces 22 b and 23 b and the top surfaces 22 t and 23 t constitute thexy plane.

The coil component 10 is a component surface-mounted on a printedcircuit board at actual use time and is mounted with bottom surfaces 22b and 23 b of the respective flange parts 22 and 23 facing the printedcircuit board. The plate core 30 is bonded by adhesive to the topsurfaces 22 t and 23 t of the respective flange parts 22 and 23. Withsuch a configuration, the drum-shaped core 20 and the plate core 30constitute a closed magnetic path.

As illustrated in FIG. 1, first to fourth terminal electrodes E1 to E4are arranged in this order in the x-direction on the bottom surface 22 band outer side surface 22 o of the flange part 22, and the fifth toeighth terminal electrodes E5 to E8 are arranged in this order in thex-direction on the bottom surface 23 b and outer side surface 23 o ofthe flange part 23. The terminal electrodes E1 to E8 are terminal metalfittings having an L-shape and bonded to the flange part 22 or 23through an adhesive. By using the L-shaped terminal metal fitting, it ispossible to reduce production cost as compared with a case where theterminal electrode E1 to E8 is formed by baking metal paste thereonto.

The four wires W1 to W4 are wound around the winding core part 21. Oneends of the wires W1 to W4 are connected to different ones of theterminal electrodes E1 to E4, and the other ends of the wires W1 to W4are connected to different ones of the terminal electrodes E5 to E8. Thewires W1 to W4 are each connected to a part of the terminal electrodethat covers the bottom surface 22 b or 23 b. Although not especiallylimited, the connection can be achieved by thermocompression or laserjoining.

Although not especially limited, the wire W1 is connected to theterminal electrodes E1 and E8, and the winding direction thereof is,e.g., clockwise. The wire W2 is connected to the terminal electrodes E2and E7, and the winding direction thereof is, e.g., counterclockwise.The wire W3 is connected to the terminal electrodes E3 and E6, and thewinding direction thereof is, e.g., clockwise. The wire W4 is connectedto the terminal electrodes E4 and E5, and the winding direction thereofis, e.g., counterclockwise.

FIGS. 2 and 3 are each a side view of the coil component 10 as seen fromthe y-direction. More specifically, FIG. 2 is a view as observed fromthe flange part 22 side, and FIG. 3 is a view as observed from theflange part 23 side.

FIG. 2 illustrates in detail the layout of the terminal electrodes E1 toE4. Assuming that the distance between the terminal electrodes E1 and E2in the x-direction is L1 and that the distance between the terminalelectrodes E3 and E4 in the x-direction is L4, the coil component 10according to the present embodiment satisfies L1>L4.

Assume that a virtual line C1 that passes a center axis A of the windingcore part 21 and extends in the z-direction is defined on the outer sidesurface 22 o. In this case, assuming that the distance between thevirtual line C1 and the terminal electrode E2 in the x-direction is L2,and the distance between the virtual line C1 and the terminal electrodeE3 in the x-direction is L3, the coil component 10 according to thepresent embodiment satisfies L2<L3. Further, L1<L2+L3 is satisfied.

Further, the distance between an x-direction right side end portion ofthe outer side surface 22 o and the terminal electrode E1 in thex-direction is L5, and the distance between an x-direction left side endportion of the outer side surface 22 o and the terminal electrode E4 inthe x-direction is L6, the coil component 10 according to the presentembodiment satisfies L5>L6.

Further, each of the terminal electrodes E1 to E4 is designed short inz-direction length so as not to overlap the winding core part 21 asviewed from the y-direction.

FIG. 3 illustrates in detail the layout of the terminal electrodes E5 toE8. Assuming that the distance between the terminal electrodes E5 and E6in the x-direction is L1 and that the distance between the terminalelectrodes E7 and E8 in the x-direction is L4, the coil component 10according to the present embodiment satisfies L1>L4.

Assume that a virtual line C2 that passes the center axis A of thewinding core part 21 and extends in the z-direction is defined on theouter side surface 23 o. In this case, assuming that the distancebetween the virtual line C2 and the terminal electrode E6 in thex-direction is L2, and the distance between the virtual line C2 and theterminal electrode E7 in the x-direction is L3, the coil component 10according to the present embodiment satisfies L2<L3. Further, L1<L2+L3is satisfied.

Further, the distance between an x-direction right side end portion ofthe outer side surface 23 o and the terminal electrode E5 in thex-direction is L5, and the distance between an x-direction left side endportion of the outer side surface 23 o and the terminal electrode E8 inthe x-direction is L6, the coil component 10 according to the presentembodiment satisfies L5>L6.

Further, each of the terminal electrodes E5 to E8 is designed short inz-direction length so as not to overlap the winding core part 21 asviewed from the y-direction.

In the present embodiment, the terminal electrodes E1 to E8 are arrangedin the above-described layout, so that when, for example, the terminalelectrodes E1 and E2 are used as a primary side input/output terminal ofthe pulse transformer, the terminal electrodes E5 and E6 are used as asecondary side input/output terminal of the pulse transformer, theterminal electrodes E7 and E8 are used as a primary side center tap ofthe pulse transformer, and the terminal electrodes E3 and E4 are used asa secondary side center tap, it is possible to reduce eddy current losswhile ensuring the withstand voltage between the primary and secondarysides. The withstand voltage between the primary and secondary sides canbe ensured by increasing the distance (L2+L3) with respect to thedistance L1 or L2.

The eddy current is generated when a magnetic flux caused by currentflowing in the wires W1 to W4 crosses the terminal electrodes E1 to E8.The coil component 10 according to the present embodiment is laid outsuch that the terminal electrodes E1 to E8 do not overlap the windingcore part 21 as viewed in the y-direction, so that occurrence of theeddy current can be suppressed.

In order to suppress occurrence of the eddy current as much as possiblein the configuration where terminal electrodes E1 to E8 do not overlapthe winding core part 21 as viewed in the y-direction, the planarpositions of the terminal electrodes E1 to E8 as viewed from they-direction should preferably be separate from the center axis A of thewinding core part 21 as much as possible. This configuration is achievedby, for example, disposing the terminal electrodes E1 and E2 as close tothe right side of FIG. 2 as possible, and the terminal electrodes E3 andE4 as close to the left side of FIG. 2 as possible. However, when theterminal electrodes E1 and E2 are used respectively as the primary sideinput/output terminals of the pulse transformer, if the distance L1between them is made excessively small, the primary side input/outputterminal pair may be short-circuited. Thus, it is necessary to ensure acertain size for the distance L1 between the terminal electrodes E1 andE2.

On the other hand, when being used as the secondary side center taps ofthe pulse transformer, the terminal electrodes E3 and E4 are appliedwith the same potential. Thus, the distance L4 between the terminalelectrodes E3 and E4 can be smaller than the distance L1 (L1>L4). As aresult, the terminal electrode E3 can be offset more outward than theterminal electrode E2 (L3>L2). This allows the distance between theterminal electrodes E3, E4 and the center axis A of the winding corepart 21 to be large, so that it is possible to reduce eddy currentgenerated in the terminal electrodes E3 and E4.

In addition, when the terminal electrodes E3 and E4 are used as thesecondary side center taps of the pulse transformer, they have the samepotential. Thus, the terminal electrodes E3 and E4 have a higher degreeof freedom in layout design than the terminal electrodes E1 and E2. Byutilizing this point, the terminal electrode E4 is disposed closer tothe end portion (L5>L6) in the present embodiment, thereby enablingfurther reduction of eddy current generated in the terminal electrodesE3 and E4.

The same is applied to the terminal electrodes E5 to E8. That is, theterminal electrode E7 is offset more outward than the terminal electrodeE6, enabling reduction of eddy current generated in the terminalelectrodes E7 and E8. In addition, the terminal electrode E8 is disposedcloser to the end portion, thereby enabling further reduction of eddycurrent generated in the terminal electrodes E7 and E8.

This is the structure of the coil component 10 according to the presentembodiment.

FIG. 4 is a plan view illustrating a conductor pattern on a substrate onwhich the coil component 10 is mounted.

In the example of FIG. 4, mounting regions 41 and 42 are assigned to asubstrate 40, and two coil components 10 are mounted in the mountingregions 41 and 42. The mounting regions 41 and 42 are laid out inproximity in the x-direction to each other for high density mounting onthe substrate 40. Specifically, the distance between the mountingregions 41 and 42 in the x-direction is L0. The minimum value of thedistance L0 is restricted by required reliability, specification,mounting accuracy, or the like.

Such a layout is required in, for example, a LAN connector circuit(100Base) illustrated in FIG. 5 and a LAN connector circuit (1000Base)illustrated in FIG. 6, when the coil component 10 according to thepresent embodiment is a pulse transformer. As illustrated in FIGS. 5 and6, these LAN connector circuits each use a plurality of pulsetransformers PT, so that when the coil components 10 are mounted at highdensity, the mounting regions 41 and 42 may be in proximity to eachother as illustrated in FIG. 4.

Land patterns P1 to P6 to be connected to the terminal electrodes E1 toE8 by a solder are provided on the mounting regions 41 and 42.Specifically, the land patterns P1, P2, P4, and P5 are connectedrespectively to the terminal electrodes E1, E2, E5, and E6. The landpattern P3 is connected to the terminal electrodes E3 and E4. The landpattern P6 is connected to the terminal electrodes E7 and E8. With thisconfiguration, the terminal electrodes E1 and E2 can be used as aprimary side input/output terminal of the pulse transformer, theterminal electrodes E5 and E6 can be used as a secondary sideinput/output terminal of the pulse transformer, the terminal electrodesE7 and E8 can be used as a primary side center tap of the pulsetransformer, and the terminal electrodes E3 and E4 can be used as asecondary side center tap.

As illustrated in FIG. 4, the width of each of the land patterns P3 andP6 in the x-direction is larger than that of each of the land patternsP1, P2, P4 and P5. This is because two terminal electrodes (e.g., E3 andE4) are connected to one land pattern (e.g., P3). However, each of theland patterns P3 and P6 does not necessarily have to cover the whole ofits corresponding two terminal electrodes in the x-direction, and isonly required to cover only a part thereof, as illustrated in FIG. 4.With this configuration, even when the distance L0 between the mountingregions 41 and 42 is small, and when the distance L6 between each of theterminal electrodes E4 and E8 and the edge of each of the mountingregions 41 and 42 is small, it is possible to ensure the distancebetween the land pattern P1 provided in the mounting region 41 and theland pattern P3 provided in the mounting region 42 in the x-direction,and the distance between the land pattern P6 provided in the mountingregion 41 and the land pattern P4 provided in the mounting region 42 inthe x-direction.

FIG. 7 is a side view of the coil component 10 mounted on the substrate40.

In the example of FIG. 7, the terminal electrode E1 and the land patternP1 are connected by a solder 51, the terminal electrode E2 and the landpattern P2 are connected by a solder 52, the terminal electrodes E3 andE4 and the land pattern P3 are connected by a solder 53. Each of theland patterns P1 and P2 has a size larger in the x-direction than thatof the corresponding one of the terminal electrodes E1 and E2. The landpattern P3 is disposed so as to cover the interval between the terminalelectrodes E3 and E4. The solders 51 to 53 supplied respectively to theland patterns P1 to P3 cover the surfaces of the terminal electrodes E1to E4 that extend in the z-direction on the outer surface 22 o of theflange part 22 to form fillets. This increases bonding strength of thecoil component 10 with respect to the substrate 40, thereby increasingreliability of the circuit board.

Further, the fillet of the solder 53 forms a bridge that directlyconnects the terminal electrodes E3 and E4. Such a bridge can be easilyformed when the distance L4 between the terminal electrodes E3 and E4 issmall. Thus, short-circuit between the terminal electrodes E3 and E4 isachieved not only through the land pattern P3 but through the bridge ofthe solder 53. Hence, the short-circuit therebetween is made morereliable.

It is apparent that the present invention is not limited to the aboveembodiments, but may be modified and changed without departing from thescope and spirit of the invention.

For example, in the coil component 10 according to the above embodiment,the L-shaped terminal metal fittings are used as the terminal electrodesE1 to E8; alternatively, the terminal electrodes E1 to E8 may be formedby baking metal paste onto the flange parts 22 and 23.

Further, the coil component 10 according to the above embodiment has theplate core 30, but it is not essential for the coil component 10according to the present invention to have the plate core 30. Even inthe case of providing the plate core 30, it is not essential for theplate core 30 to be provided on the top surfaces 22 t and 23 t of therespective flange parts 22 and 23, as in the case of the firstembodiment, but the plate core 30 may be provided on the yz sidesurfaces of the respective flange parts 22 and 23 so as to connect theflange parts 22 and 23. Further alternatively, the plate core 30 may beprovided on the top surfaces 22 t and 23 t and yz side surfaces of therespective flange parts 22 and 23. In this case, a plate core having anL-shaped cross section obtained by integrally forming a part that coversthe top surfaces 22 t and 23 t and a part that covers the yz sidesurfaces may be used.

Further, it is not essential for each of the terminal electrodes E1 toE8 to have an L-shape. For example, the terminal electrodes E1 to E4 maybe formed into a U-like shape that covers also the top surface 22 t ofthe flange part 22, and the terminal electrodes E5 to E8 may be formedinto a U-like shape that covers also the top surface 23 t of the flangepart 23.

What is claimed is:
 1. A circuit board comprising: a substrate having aplurality of land patterns; and a coil component mounted on thesubstrate, wherein the coil component comprising: a drum-shaped coreincluding: a winding core part, an axial direction of the winding corepart being a first direction; a first flange part provided at one end ofthe winding core part in the first direction; and a second flange partprovided at other end of the winding core part in the first direction;first to fourth terminal electrodes formed on the first flange part soas to be arranged in this order in a second direction substantiallyperpendicular to the first direction; fifth to eighth terminalelectrodes formed on the second flange part so as to be arranged in thisorder in the second direction; and first to fourth wires wound aroundthe winding core part, one ends of the first to fourth wires beingconnected to different ones of the first to fourth terminal electrodesand other ends of the first to fourth wires being connected to differentones of the fifth to eighth terminal electrodes, wherein the firstflange part has a first inner side surface connected to the winding corepart and a first outer side surface opposite to the first inner sidesurface, the second flange part has a second inner side surfaceconnected to the winding core part and a second outer side surfaceopposite to the second inner side surface, the first to fourth terminalelectrodes are formed at least on the first outer side surface, thefifth to eighth terminal electrodes are formed at least on the secondouter side surface, a distance between the first and second terminalelectrodes in the second direction is larger than the distance betweenthe third and fourth terminal electrodes in the second direction, adistance between the fifth and sixth terminal electrodes in the seconddirection is larger than the distance between the seventh and eighthterminal electrodes in the second direction, a distance between a firstvirtual line and the third terminal electrode in the second direction islarger than a distance between the first virtual line and the secondterminal electrode in the second direction, where the first virtual lineis defined on the first outer side surface, extends in a third directionsubstantially perpendicular to the first and second directions, andwhose position in the second direction coincides with the center axis ofthe winding core part, a distance between a second virtual line and theseventh terminal electrode in the second direction is larger than adistance between the second virtual line and the sixth terminalelectrode in the second direction, where the second virtual line isdefined on the second outer side surface, extends in the thirddirection, and whose position in the second direction coincides with thecenter axis of the winding core part, and the plurality of land patternsinclude first, second, third, and fourth land patterns connectedrespectively to the first, second, fifth, and sixth terminal electrodes,a fifth land pattern connected in common to the third and fourthterminal electrodes, and a sixth land pattern connected in common to theseventh and eighth terminal electrodes.
 2. The circuit board as claimedin claim 1, wherein the third and fourth terminal electrodes areshort-circuited by a bridge of a solder, and wherein the seventh andeighth terminal electrodes are short-circuited by a bridge of anothersolder.